The present invention relates to an electric motor casing with forced air cooling.
It has been long known to manufacture the casings or shells of electric motors using two coaxial cylindrical jackets mutually connected at the end thereof by the motor head plates, in order to produce a cylindrical chamber through which air flows, impelled by a fan mounted on the motor shaft proximate to one of the head plates, said air escaping through holes on the other of the head plates.
Several disadvantages of these known casings are related to the fact that the airflow is rather turbulent inside the interspace defined by the two jackets as there is no appropriate means for conveying said flow, thus reducing the efficiency of the cooling and furthermore causing considerable noise.
The assembly costs of this type of casing are furthermore notably high and detrimental to the production costs of the entire motor.
It is an aim of the present invention to provide a motor casing which eliminates the above mentioned disadvantages, improves the operating characteristics of the unit and requires simplified assembly operations in order to reduce the corresponding production costs.
Within the scope of the above described aim, it is a particular object of the present invention to provide a motor casing whose assembly requires no tedious and time-waisting operation normally needed for centering the double jacket before mounting the end head plates.
A further object of the present invention is to make the flow of cooling air within the interspace between the two jackets more regular and uniform, rendering it substantially laminar, so as to generally improve the cooling of the motor and increase its overall efficiency while reducing the operating noise.